AO3

• Reliability of Diagnosis: same patient = same diagnosis given
• Validity of Diagnosis: are we measuring Sz? unique syndrome? gender/culture bias?
• Co-Morbidity (P + E):

  P/def: two conditions occurring in the same patient

  E: Buckley et al. concluded that around 1/2 of patients diagnosed with Sz also have a depression diagnosis (50%) -> substance abuse (47%) -> PTSD occurred in 29% -> OCD in 23%
• Co-Morbidity (A):

  A: has potential to lower validity of diagnosis -> as patients are displaying several different 'sets' of symptoms -> its therefore difficult to recognise in them the accurate diagnosis

  A: may also mean the classification system isn't accurate/valid -> if so many people have the same disorders (e.g. Sz + depression) then perhaps they are part of a single disorder + have a single cause
• Symptom Overlap (P + E):

  P/def: two or more conditions share symptoms

  E: theres considerable overlap between symptoms of Sz and other conditions -> e.g. Sz + bipolar disorder involve positive symptoms (delusions) + negative symptoms (abolition) -> e.g. depression shares Sz symptoms such as avolitions
• Symptom Overlap (A):

  A: has the potential to lower the validity of diagnosis -> because many disorders are similar in their symptom lists -> therefore difficult to recognise in them the accurate diagnosis
• Gender Bias (P + E):

  P/def: one gender is diagnosed more often - not due to biological factors

  E: Longnecker et al. reviewed prevalence of Sz studies -> concluded that since 1980s, men have been diagnosed with Sz more often than women -> prior to this there appears to be no difference

  E: Cotton et al. found that female Sz patients typically function better than men (better at masking symptoms), they're more likely to work + have good family relationships
• Gender Bias (A):

  A: also suggests that the classification system may have been created on only male samples so that the Sz criteria are androcentric -> lowering the validity of the classification

  A: has the potential to lower the validity of diagnosis -> because females may mask symptoms better/mental health practitioners may pay less attention to them due to their own bias -> therefore difficult to gain an accurate diagnosis
• Culture Bias (P + E):

  P/def: some cultures have higher prevalence - not due to genetic vulnerability

  E: African Americans + English people of Afro-Caribbean origin are more likely to be diagnosed with Sz than white people

  E: given that rates in Africa aren't particularly high, this is most certainly not due to genetic vulnerability.
• Culture Bias (A):

  A: has the potential to lower the validity of the diagnosis -> because mental health practitioners may see symptoms presented by Afro-Carribeans as more abnormal due to their own bias -> therefore its difficult to gain an accurate diagnosis
• Subjectivity (P + E):

  P: the tendency to interpret data or make judgements in the light of personal feelings, beliefs or experiences

  E: Cheniaux et al. found that when 2 psychiatrists independently diagnosed 100 patients using both systems:

  • Psychiatrist 1: ICD-10 = 44 DSM-5 = 26
  • Psychiatrist 2: ICD-10 = 24 DSM-5 = 13
• Subjectivity (A):

  A: this lowers the reliability of classification -> the criteria are not sufficiently distinct to be usable by the different psychiatrists reliably

  A: has the potential to lower the reliability of diagnosis -> because there may be subjective interpretation of the criteria by different psychiatrists -> diagnosis is therefore biased